/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.codec.rtsp;
import java.util.regex.Pattern;
import io.netty.handler.codec.http.DefaultFullHttpRequest;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.DefaultHttpRequest;
import io.netty.handler.codec.http.DefaultHttpResponse;
import io.netty.handler.codec.http.HttpMessage;
import io.netty.handler.codec.http.HttpObjectDecoder;
import io.netty.handler.codec.http.HttpResponseStatus;
/**
* Decodes {@link io.netty.buffer.ByteBuf}s into RTSP messages represented in
* {@link HttpMessage}s.
* <p>
* <h3>Parameters that prevents excessive memory consumption</h3>
* <table border="1">
* <tr>
* <th>Name</th><th>Meaning</th>
* </tr>
* <tr>
* <td>{@code maxInitialLineLength}</td>
* <td>The maximum length of the initial line
* (e.g. {@code "SETUP / RTSP/1.0"} or {@code "RTSP/1.0 200 OK"})
* If the length of the initial line exceeds this value, a
* {@link io.netty.handler.codec.TooLongFrameException} will be raised.</td>
* </tr>
* <tr>
* <td>{@code maxHeaderSize}</td>
* <td>The maximum length of all headers. If the sum of the length of each
* header exceeds this value, a {@link io.netty.handler.codec.TooLongFrameException} will be
* raised.</td>
* </tr>
* <tr>
* <td>{@code maxContentLength}</td>
* <td>The maximum length of the content. If the content length exceeds this
* value, a {@link io.netty.handler.codec.TooLongFrameException} will be raised.</td>
* </tr>
* </table>
*/
public class RtspDecoder extends HttpObjectDecoder {
/**
* Status code for unknown responses.
*/
private static final HttpResponseStatus UNKNOWN_STATUS =
new HttpResponseStatus(999, "Unknown");
/**
* True if the message to decode is a request.
* False if the message to decode is a response.
*/
private boolean isDecodingRequest;
/**
* Regex used on first line in message to detect if it is a response.
*/
private static final Pattern versionPattern = Pattern.compile("RTSP/\\d\\.\\d");
/**
* Constant for default max initial line length.
*/
public static final int DEFAULT_MAX_INITIAL_LINE_LENGTH = 4096;
/**
* Constant for default max header size.
*/
public static final int DEFAULT_MAX_HEADER_SIZE = 8192;
/**
* Constant for default max content length.
*/
public static final int DEFAULT_MAX_CONTENT_LENGTH = 8192;
/**
* Creates a new instance with the default
* {@code maxInitialLineLength (4096)}, {@code maxHeaderSize (8192)}, and
* {@code maxContentLength (8192)}.
*/
public RtspDecoder() {
this(DEFAULT_MAX_INITIAL_LINE_LENGTH,
DEFAULT_MAX_HEADER_SIZE,
DEFAULT_MAX_CONTENT_LENGTH);
}
/**
* Creates a new instance with the specified parameters.
* @param maxInitialLineLength The max allowed length of initial line
* @param maxHeaderSize The max allowed size of header
* @param maxContentLength The max allowed content length
*/
public RtspDecoder(final int maxInitialLineLength,
final int maxHeaderSize,
final int maxContentLength) {
super(maxInitialLineLength, maxHeaderSize, maxContentLength * 2, false);
}
/**
* Creates a new instance with the specified parameters.
* @param maxInitialLineLength The max allowed length of initial line
* @param maxHeaderSize The max allowed size of header
* @param maxContentLength The max allowed content length
* @param validateHeaders Set to true if headers should be validated
*/
public RtspDecoder(final int maxInitialLineLength,
final int maxHeaderSize,
final int maxContentLength,
final boolean validateHeaders) {
super(maxInitialLineLength,
maxHeaderSize,
maxContentLength * 2,
false,
validateHeaders);
}
@Override
protected HttpMessage createMessage(final String[] initialLine)
throws Exception {
// If the first element of the initial line is a version string then
// this is a response
if (versionPattern.matcher(initialLine[0]).matches()) {
isDecodingRequest = false;
return new DefaultHttpResponse(RtspVersions.valueOf(initialLine[0]),
new HttpResponseStatus(Integer.parseInt(initialLine[1]),
initialLine[2]),
validateHeaders);
} else {
isDecodingRequest = true;
return new DefaultHttpRequest(RtspVersions.valueOf(initialLine[2]),
RtspMethods.valueOf(initialLine[0]),
initialLine[1],
validateHeaders);
}
}
@Override
protected boolean isContentAlwaysEmpty(final HttpMessage msg) {
// Unlike HTTP, RTSP always assumes zero-length body if Content-Length
// header is absent.
return super.isContentAlwaysEmpty(msg) || !msg.headers().contains(RtspHeaderNames.CONTENT_LENGTH);
}
@Override
protected HttpMessage createInvalidMessage() {
if (isDecodingRequest) {
return new DefaultFullHttpRequest(RtspVersions.RTSP_1_0,
RtspMethods.OPTIONS, "/bad-request", validateHeaders);
} else {
return new DefaultFullHttpResponse(RtspVersions.RTSP_1_0,
UNKNOWN_STATUS,
validateHeaders);
}
}
@Override
protected boolean isDecodingRequest() {
return isDecodingRequest;
}
}